1. Field of the Invention
The present invention relates to a two-part bending endoscope including in an insertion portion of the endoscope a bending portion configured by including a first bending part and a second bending part.
2. Description of the Related Art
An endoscope has an elongated insertion portion configured to be inserted into a body. The insertion portion is inserted into a lumen such as a stomach, intestines, or the like. A lumen has a sterically and intricately curved shape. Therefore, when the insertion portion is inserted into a deep part inside the sterically curved lumen, it is necessary to sterically curve the insertion portion in accordance with the luminal shape.
Japanese Patent Application Laid-Open Publication No. 2003-220022 (hereinafter, referred to as a patent document) discloses an endoscope with second bending part (hereinafter, referred to as a two-part bending endoscope). The two-part bending endoscope includes, on a distal end portion side of an insertion portion in the following order from the distal end, a first bending part and a second bending part which are provided in a linked manner. The two-part bending endoscope includes a first bending knob for bending the first bending part and a second bending knob for bending the second bending part at an operation portion provided on the proximal end side of the insertion portion.
According to the two-part bending endoscope, the first bending part is bent by the operation of the first bending knob, on the other hand, the second bending part is bent by the operation of the second bending knob, thereby enabling smooth insertion of the insertion portion into an intricately curved lumen.
Now, description will be made on a procedure for inserting an insertion portion from a duodenum into a biliary tract, for example, by using the two-part bending endoscope.
As shown in FIG. 1, an operator causes the first bending part 101 configuring the insertion portion 100 to bend and causes an observation optical system, not shown, of the distal end portion 103 to face an orifice portion of the biliary tract 110. Then, an image in the vicinity of the biliary tract 110 is displayed on a screen (not shown).
Next, the operator appropriately operates the first bending knob and the second bending knob, which are not shown, while observing the screen. Then, the operator causes the first bending part 101 and the second bending part 102 to bend, to insert the insertion portion 100 into the deep part of the biliary tract 110 as shown by the arrow Y2 in FIG. 2.
Note that the reference numeral 104 represents a flexible tube portion and the reference numeral 111 represents the duodenum.
The two-part bending endoscope disclosed in the above patent document has a configuration in which the first bending part independently pedal ins a bending action by the operation of the first bending knob, and the second bending part independently performs a bending action by the operation of the second bending knob. Therefore, if the operator causes the second bending part 102 to bend in a state where the first bending part 101 is bent as shown by the solid lines in FIG. 1, the first bending part 101 and the distal end portion 103 move as shown by the dashed lines in conjunction with the bending of the second bending part 102. When the distal end portion 103 moves as shown by the dashed lines, the image of the biliary tract 110 displayed at the center of the screen, for example, gradually deviates from the screen according to the bending of the second bending part 102.
A technically accomplished operator causes two bending parts to bend as shown below, in order to prevent the image of the biliary tract 110 from deviating from the center of the screen in conjunction with the bending of the second bending part 102. That is, in order to constantly display the image of the biliary tract 110 on the screen, an experienced technician has repeatedly performed a second operation for bending the second bending part 102 in a desired direction by a desired amount and a first operation for bending the first bending part 101 in a direction opposite to the bending direction of the second bending part 102 by a desired amount.